So what does that mean for Jennifer's diet? Essentially, she'll need to find sources of protein that aren't animal-based—and she'll need to make sure to get enough nutrients like calcium and vitamin D.

There are plenty of benefits of going vegan—but only if done the right way. "It's not a weight-loss diet," says Jaclyn London, M.S., R.D., a senior dietician at Mount Sinai Hospital in New York City. "The idea behind going vegan is to retool a diet that’s generally too high in saturated fats and calories, with an emphasis on decreasing processed foods."

If you think the vegan lifestyle could be right for you, even if it's just part-time, here are a few key principles to help you make the transition:

Think Inclusion, Not Elimination
If you're focusing on all the foods you can't eat—eggs, milk, chicken, fish, etc., etc.—then veganism is going to be a rough path for you. Instead, focus on new foods you can include in your diet that you may not have considered before. This can range from non-dairy milk options like almond, soy, and hemp milk, all the way to new sources of healthy fats like chia seeds and flax seeds. "It's important to think about what's new in your diet," says London. In doing so, you avoid the punishment mentality of many strict regimens.

Watch Your Processed Food Intake
Because veganism does reduce your field of options, it's easy to start to rely on processed or unhealthy foods. But loading up on vegan cookies or getting French fries when you go out to eat—because it's one of the few things you know is vegan—will only leave you cranky and nutrient-deprived. "You want to find healthier sources of nutrients, not buy the fake version of the item you're no longer eating," says London. That means you should be blending up frozen bananas to get a summer-y treat, not stocking your freezer with vegan ice cream.

Strive for Variety
Just like with non-vegans, it's important to vary the foods you’re consuming on a daily basis to ensure you're getting all of the nutrients you need. London notes that vegan diets often lack the right nutrient balance since avoiding animal by-products can naturally skew the vitamins and minerals you're consuming. Check out the Vegetarian Resource Group for a list of healthy foods that will help you get enough of each key nutrient, including protein, omega-3 fatty acids, iron, zinc, iodine, and vitamins D and B12. Then work a wide mix of these ingredients into your meals and snacks.